<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Vue监听数据改变的原理</title>
    </title>
    <!-- 引入vue -->
    <script type="text/javascript" src="../js/vue.js"></script>
</head>

<body>
    <script type="text/javascript">

        let data = {
            name: 'yykk',
            address: '北京',
        }

        //创建一个监视的实例对象，用于监视data中属性的变化
        const obs = new Observer(data)
        console.log(obs)

        //准备一个vm实例对象
        let vm = {}
        vm._data = data = obs

        function Observer (obj)
        {
            //汇总对象中所有的属性形成一个数组
            const keys = Object.keys(obj)
            //遍历
            keys.forEach((k) =>
            {
                Object.defineProperty(this, k, {
                    get ()
                    {
                        return obj[k]
                    },
                    set (val)
                    {
                        console.log(`${k}被改了，我要去解析模板，生成虚拟DOM.....我要开始忙了`)
                        obj[k] = val
                    }
                })
            })
        }
    </script>
</body>

</html>